While both the pectoralis major and pectoralis minor muscles control the movements of the arm, the pectoralis major is specifically responsible for its lateral, vertical and rotational movement. In addition to this primary function, both pectoral muscles also aid in the action of deep breathing.Continue Reading
Each human has two pectoralis major muscles, one on either side of the chest. In addition, two triangular pectoralis minor muscles lie below each pectoralis major muscle and aid them in their functions. In common terms, especially in sports, all of these muscles are collectively referred to simply as the "pecs."
The pectoralis major fans across the chest, beginning at the clavicular head, sternocostal head, and anterior surface of the sternum and inserting at the lateral lip of the intertubercular groove of the the humerus. This allows the muscle, located primarily in the chest, to control the movement of the arm, its major function.
The location of the pectoralis major across the chest, however, also allows it to aid in the movements of deep breathing. In this case, the pecs pull the ribcage out, allowing the lungs room to expand.
In addition, each pectoralis major has six separate sets of muscle fibers that are capable of independent movement through the central nervous system.Learn more about Muscles
The antagonist muscles of the pectoralis minor, a muscle that runs across the front of the chest, include the trapezius, rhomboid major and minor, and the levator scapulae, states Wellness Digest. The pectoralis minor protracts the scapula, or moves it away from the spine.Full Answer >
Deltoid muscles, situated in the shoulders, are responsible for the majority of arm movements, including arm abduction, arm flexion and medial rotation, and arm extension and lateral rotation. These movements involve the deltoids working with the rotator cuff muscles, supraspinatus, pectoralis major, infraspinatus, terres minor and terres major.Full Answer >
The main purpose of the gastrocnemius muscle is to facilitate leg movements, such as jumping, walking, running and knee bending. The gastrocnemius muscle pushes the leg down during these types activities. The location of this muscle is the back of the leg on the calf area.Full Answer >
The structure of muscle tissue varies depending upon whether the muscle controls voluntary or involuntary movements, according to the National Cancer Institute. There are three types of muscle: skeletal, smooth and cardiac. Skeletal muscle is striated, smooth muscle is non-striated and cardiac muscle has characteristics of both.Full Answer >